In this problem, use the fact that the force of gravity on a particle of mass m at the point with position vector is GMmr F ]][* where G is a constant and M is the mass of the earth. Calculate the work done by the force of gravity on a particle of mass m as it moves radially from 6000 km to 7600 km from the center of the earth. Work (GMm)/7600+GMm/6000 (Your answer may involve the constants m, M and G.)